The present invention is directed to the field of trapping, in particular, small traps of the type used for catching small animals in the wild for food and pelts, e.g. rabbits, foxes, raccoons, etc. It is also common to set such trap to catch vermin and pests, e.g. skunks, rats, etc.
A common-type trap 10 is shown in FIG. 1. A pair of co-acting jaws 12a, 12b are used to securely engage the leg or other member of a captured animal. The ends of the jaws 12a, 12b are pivotally connected to a body portion 14 for pivotal displacement between an opened position (for a set trap) and a closed position (for engagement with a captured animal). A pair of levers 16 are loaded with a biasing force from an arrangement of springs 18. In this way, the levers 16 bias the jaws 12a, 12b into the closed position. To set the trap, as shown in FIG. 2A, the levers 16 are depressed, loading the springs 18 and allowing the jaws 12a, 12b to be placed in the opened position, along a level line A—A as shown in FIGS. 1, 2A and 2B. A first jaw 12a is placed level and a dog 20 is laid over the top of the jaw 12a. The end of the dog 20 is placed underneath a pan 22. In this way, the dog 20 and the pan 22 retain the jaws 12a, 12b in the opened position, with the spring-biased levers 16 fully loaded. When an animal steps on the pan 22, the pan 22 tilts to release the dog 20, which in turn releases the jaw 12a and springs the trap, where the loaded levers 16 pivot the jaws 12a, 12b to the closed position, securely capturing the animal.
As shown in FIG. 2A, only the first jaw 12a is securely retained by the dog 20. The second jaw 12b is allowed to lay loose. This results in a problem known as “jaw lift.” When the trap 10 is loaded, a the first jaw 12a applies a torsional twist to the levers 16, causing one side to of each lever to be depressed and the other side to be elevated. The first jaw 12a lays on top of the depressed side, and is retained in a position flat with respect to the level line A—A. The second jaw 12b is not firmly retained, and sits on top of the elevated side of the levers 16. In this way, the second jaw 12b thus tends to sit a little higher than the first jaw 12a. As a result, the second jaw 12b tends to lift, lying at an angle to line A—A as shown by line B in FIGS. 2A and 2B. In operation, it can happen that the animal may bump the lifted jaw 12b and swing it onto the retained jaw 12a. In this event, the trap 10 can be sprung without capturing the animal. Many previous approaches have been made to address this well known problem. However, such approaches create other problems with trap function and none are known to provide a satisfactory solution.